CVE-2026-104021
Fastcache by Host.it <= 1.7.4 - Authenticated (Administrator+) Code Injection via .htaccess Directive Injection via 'cache_cookie_exclude' Setting
The Fastcache by Host.it plugin for WordPress is vulnerable to Code Injection in all versions up to, and including, 1.7.4 via the fastcache_settings[cache_cookie_exclude][] parameter. This is due to the plugin registering the cache_cookie_exclude setting via register_setting() without a sanitize_callback, while buildSiteHtaccessRules() applies only trim() to each cookie value before interpolating it directly into an Apache RewriteCond line — a normalization that strips surrounding whitespace but leaves embedded newlines intact, allowing an attacker to break out of the capture group and append arbitrary directives. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary Apache directives into the site's .htaccess file via file_put_contents(), enabling server-level configuration changes such as setting php_value auto_prepend_file to execute attacker-controlled PHP code on every request.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.2
Fastcache by Host.it <= 1.7.4 - Authenticated (Administrator+) Code Injection via .htaccess Directive Injection via 'cache_cookie_exclude' Setting
The Fastcache by Host.it plugin for WordPress is vulnerable to Code Injection in all versions up to, and including, 1.7.4 via the fastcache_settings[cache_cookie_exclude][] parameter. This is due to the plugin registering the cache_cookie_exclude setting via register_setting() without a sanitize_callback, while buildSiteHtaccessRules() applies only trim() to each cookie value before interpolating it directly into an Apache RewriteCond line — a normalization that strips surrounding whitespace but leaves embedded newlines intact, allowing an attacker to break out of the capture group and append arbitrary directives. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary Apache directives into the site's .htaccess file via file_put_contents(), enabling server-level configuration changes such as setting php_value auto_prepend_file to execute attacker-controlled PHP code on every request.
- Record
CVE-2026-104021- CVSS 3.1
- 7.2 High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
EUVDEUVD-2026-96068
7.2
The Fastcache by Host.it plugin for WordPress is vulnerable to Code Injection in all versions up to, and including, 1.7.4 via the fastcache_settings[cache_cookie_exclude][] parameter. This is due to the plugin registering the cache_cookie_exclude setting via register_setting() without a sanitize_callback, while buildSiteHtaccessRules() applies only trim() to each cookie value before interpolating it directly into an Apache RewriteCond line — a normalization that strips surrounding whitespace but leaves embedded newlines intact, allowing an attacker to break out of the capture group and append arbitrary directives. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary Apache directives into the site's .htaccess file via file_put_contents(), enabling server-level configuration changes such as setting php_value auto_prepend_file to execute attacker-controlled PHP code on every request.
- Record
EUVD-2026-96068- CVSS 3.1
- 7.2 High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-hm53-mjmf-w6v4
7.2
The Fastcache by Host.it plugin for WordPress is vulnerable to Code Injection in all versions up...
The Fastcache by Host.it plugin for WordPress is vulnerable to Code Injection in all versions up to, and including, 1.7.4 via the fastcache_settings[cache_cookie_exclude][] parameter. This is due to the plugin registering the cache_cookie_exclude setting via register_setting() without a sanitize_callback, while buildSiteHtaccessRules() applies only trim() to each cookie value before interpolating it directly into an Apache RewriteCond line — a normalization that strips surrounding whitespace but leaves embedded newlines intact, allowing an attacker to break out of the capture group and append arbitrary directives. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary Apache directives into the site's .htaccess file via file_put_contents(), enabling server-level configuration changes such as setting php_value auto_prepend_file to execute attacker-controlled PHP code on every request.
- Record
GHSA-hm53-mjmf-w6v4- CVSS 3.1
- 7.2 High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
NVD
7.2
The Fastcache by Host.it plugin for WordPress is vulnerable to Code Injection in all versions up to, and including, 1.7.4 via the fastcache_settings[cache_cookie_exclude][] parameter. This is due to the plugin registering the cache_cookie_exclude setting via register_setting() without a sanitize_callback, while buildSiteHtaccessRules() applies only trim() to each cookie value before interpolating it directly into an Apache RewriteCond line — a normalization that strips surrounding whitespace but leaves embedded newlines intact, allowing an attacker to break out of the capture group and append arbitrary directives. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary Apache directives into the site's .htaccess file via file_put_contents(), enabling server-level configuration changes such as setting php_value auto_prepend_file to execute attacker-controlled PHP code on every request.
- Record
CVE-2026-104021- CVSS 3.1
- 7.2 High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-104021 is a high vulnerability (CVSS 7.2) in Hostspa Fastcache By Host.it, published October 10, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.39%, the 33rd percentile. No source names a fixed version.
References
wordfence.com/threat-intel/vulnerabilities/id/d72d7a21-0bea-4a32-b92b-326f47998b80?source=cve
plugins.trac.wordpress.org/browser/fastcache-by-host-it/tags/1.7.4/src/Core/Platform/Utility.php
plugins.trac.wordpress.org/browser/fastcache-by-host-it/tags/1.7.4/src/Dispatcher.php
plugins.trac.wordpress.org/browser/fastcache-by-host-it/tags/1.7.4/src/Admin.php
plugins.trac.wordpress.org/changeset?reponame=&old=3735944%40fastcache-by-host-it&new=3735944%40fastcache-by-host-it
nvd.nist.gov/vuln/detail/CVE-2026-104021
github.com/advisories/GHSA-hm53-mjmf-w6v4